Platelets play an essential role in the complex process of thrombus formation. Disruption of mitochondrial membrane and its membrane potential, can lead to inefficient ATP production, excessive ROS production, oxidation of protein, and fatty acids, and subsequent apoptosis. Interestingly, platelets do not have a nucleus to mediate many of the major components of apoptosis (e.g. DNA damage and fragmentation) and response to apoptosis. We and others have recently demonstrated platelet apoptosis in diabetes mellitus (DM) leading to increased thrombosis. There is an urgent need identify new mechanisms, and develop new therapies, to target platelet apoptosis and thrombosis, for the growing population of diabetic patients. We now present new preliminary results demonstrating mitochondrial dysfunction and apoptosis in diabetic platelets. Moreover activation of a novel mitophagy process appears to protect the platelet from apoptosis. Additionally, prostacyclin and epoxyeicosaenoic acid (arachidonic acid metabolites) may also protect diabetic platelets from apoptosis and thrombosis. Based on our Preliminary Results we hypothesize that mitochondrial dysfunction in platelets, arising from hyperglycemia, leads to platelet apoptosis and increased thrombosis. Through three Specific Aims we will decipher the mechanism by which hyperglycemia induces platelet mitochondrial dysfunction and assess pathways distal to platelet mitochondrial dysfunction leading to apoptosis (Specific Aim #1). We will additionally study the process of mitophagy, and how this impacts platelet mitochondrial function and apoptosis (Specific Aim #2). Specific Aim #3 will determine whether epoxyeicosaenoic acid and prostacyclin, two potentially novel therapeutic approaches, can protect against mitochondrial dysfunction and apoptosis in diabetes mellitus. Our team of internationally recognized experts in the areas of platelet biology, mitochondrial biology and apoptosis will in the short term decipher important new mechanisms regulating mitochondrial dysfunction and apoptosis in diabetes mellitus. In the long term we will have identified new targets for novel therapy against platelet mediated thrombosis.